This invention relates to work and tool holders, and particularly concerns an apparatus for refinishing sloped surfaces of wedge-shaped gate valve elements.
Gate valves typically comprise a wedge-shaped valve element or gate positionable between two opposed annular seating surfaces. Sloped surfaces of the wedge-shaped element, as well as the seating surfaces, frequently require refinishing because of corrosion or wear. U.S. patent application Ser. No. 840,453 (filed Oct. 7, 1977 and abandoned in favor of U.S. patent application 004,125, filed Jan. 17, 1979, now U.S. Pat. No. 4,205,495 incorporated herein by reference, discloses a compact tool of small weight for refinishing the seating surfaces of gate valves. Basically, the tool comprises an abrasive means mounted by a swivel joint which is rotatably driven. An external power source imparts rotational motion to a drive train contained in a pivotal housing element for ultimately rotating the swivel joint and abrasive means. The tool is insertable into the gate valve (after the valve operating mechanisms, including the wedge-shaped valve element, have been removed) so that the abrasive element thereof is in proximity to the annular valve seating surfaces to be refinished.
Since gate valves are often utilized in high pressure environments, the wedge-shaped valve elements employed therein are frequently of a very hard and weighty composition, such as Stellite, for example. In order to refinish the sloped surfaces of such an element, the element must be securely mounted in a durable and sturdy work holder. However, presently known holders are quite bulky, heavy, and provide no convenient and precise way of appropriately orienting the sloped surface of a valve element with respect to a refinishing tool.